Efficient removal of fly ash particles from high temperature flue gas is one of the most important technologies to be developed for realizing advanced high efficiency coal utilization systems such as an integrated coal gasification combined cycle (IGCC), and ceramics filtering systems have been considered for this purpose. On the other hand, high-temperature electrostatic precipitator systems also have a high possibility to be used for gas clean-up in IGCC.But in this case, high-pressure condition should be required to maintain corona discharge. The purpose of this study is to clarify separated effects of temperature and pressure on various electric and thermal phenomena in the high-temperature and high-pressure electrostatic precipitator and to obtain fundamental knowledges necessary to develop a highly efficient high-temperature and high-pressure electrostatic precipitator. For this purpose, one-dimensional cylindrical electrostatic precipitator with a thin wire electrode at the cent
… Moreerline has been constructed and effects of temperature and pressure on various electric and thermal phenomena have been derived separately and then coupled effect of them on precipitation performances have been clarified.Drastic decrease of collection efficiency at high temperature can be qualitatively explained by decrease of ion formation rate near the center electrode, decrease of particle charging rate and decrease of particle drift velocity with high kinematic viscosity and this result can be well explained by the dependency of mean free path on the temperature. The discharge mode should have changed from corona to glow mode. So, applying high pressure is definitely necessary to maintain high performance and low energy consumption in a high-temperature electrostatic precipitator.本研究により得られた主な結果は以下の通りである。(1)常圧下で等しい印加電圧のもとでは、温度の上昇とともに電流値が急増し電力消費が増大する。また、常温下で等しい印加電圧のもとでは、圧力の上昇により電流値が減少する。(2)理論的検討の結果、(1)の現象は、平均自由行程の温度・圧力依存性によって良く説明でき、高温電気集塵で高電圧印加・微小電流値のコロナ放電を維持するためには、高圧化が極めて有効であることが明かとなった。(3)常圧下で等しい電流値のもとでは、温度の上昇とともに集塵効率は低下する。この現象を、グロー放電化に伴う中心細線近傍の電界低下によるイオン発生量の減少、粒子荷電速度の減少、粘性係数の増加による粒子の移動速度の低下により理論的に説明することを試みたが、定性的には傾向を説明できるものの、定量的には今のところ十分満足のいく結果に至っていない。(4)高温高圧電気集塵特性に関する基礎的な特性を把握することができた。 Less